Apparatus for drying and finishing pulp articles



y 3, 1955 w. H. RANDALL ET AL 2,752,830

APPARATUS FOR DRYING AND FINISHING PULP ARTICLES Filed Oct. 15, 1951 8Sheets-Sheet 1 INVEN T0128 WALTER ERA/(HALL & RICHARD L .E'MEKY WATTORNEy 3, 1956 w. H. RANDALL ET AL 2,752,830

APPARATUS FOR DRYING AND FINISHING PULP ARTICLES 8 Sheets-Sheet 2 FiledOct. 15, 1951 W mm a M N wflw w H IR a2 W&

1956 w. H. RANDALL ET AL 2,752,830

APPARATUS FOR DRYING AND FINISHING PULP ARTICLES Filed Oct. 15, 1951 8sheets-Sheet 3 m h Q N N NVENTORS WALTERH.E4NDALL 8(RICHARDLE'MERY July3, 1956 w. H. RANDALL ET AL 2,752,330

APPARATUS FOR DRYING AND FINISHING PULP ARTICLES Filed Oct. 15, 1951 8Sheets-Sheet 4 I NVENTORS WAL TER H. RANDALL & RICHARD L .EMERY y 3,1956 w. H. RANDALL ETAL 2,752,830

APPARATUS FOR DRYING AND FINISHING PULP ARTICLES Filed Oct. 15, 1951 8Sheets-Sheet 5 Q N o R? r Q Q N 31 s o a a O m i s, w N W A I! I I I I Il l k l I l I l l N N $1 $3 v N N l X Q INVENTDRS WALTERIiRANDALLS'RICIL4RD L .E'MERV WA TTORN July 3, 1956 w. H. RANDALL ETAL 2,752,830

APPARATUS FOR DRYING AND FINISHING PULP ARTICLES 8 Sheets-Sheet 6 FiledOct. 15, 1951 L 0mm R W m m W 5 W60 V. j

Jufly 3, 1956 w. H. RANDALL ET AL 2,

APPARATUS FOR DRYING AND FINISHING PULP ARTICLES Filed Oct. 15, 1951 8Sheets-Sheet 7 IN V EN TOR$ WAL TE'R H. RANDALL BY 8 RICHARDL.EME'RYWATTOR/V Y MM 3,. 1956 w. H. RANDALL ET AL 2,752,830

APPARATUS FOR DRYING AND FINISHING PULP ARTICLES Filed Oct. 15, 1951 8Sheets-Sheet 8 INVENTORS WALTERH.RAN.DALL {ERICHARDL.EME'EY UnitedStates Patent APPARATUS FOR DRYILNG AND FINISHING PULP ARTICLES WalterH. Randall and Richard L. Emery, Water-ville, Maine, assignors to KeyesFibre Company, Portland, Maine, a corporation of Maine Application@ctoher 15, 1951, Serial No. 251,411

9 (Claims. (Cl. 92-59) This invention relates to the pressing andfinishing of molded pulp articles after they have been formed to substantially the desired shape.

When molded pulp articles are formed they contain a relatively largeamount of water which must be removed. In the past this water has beenremoved by subjecting the wet articles to several types of dryingoperations. In one of these, the freshly molded wet article is pressedbetween heated dies corresponding in shape to those with which thearticles are formed. This calls for the use of a relatively large numberof expensive dies. Many types of articles, and particularly those whosedimensions or shapes are not critical, can be dried without the use ofaccurately shaped heating dies, as for example by merely passing them infreely supported condition on a conveyor belt through a steam heateddrying tunnel. This so called free-drying technique is much lessexpensive than drying them between carefully machined heated dies.However, free drying results in at least a small amount of warpage, andthe final article has a somewhat fluffy and rough surface appearance.Such an article is often unacceptable to the trade because of the crudeappearance and shape. This is particularly true if such an article is tobe sold or used on the basis of its better appearance.

Among the objects of the present invention is the provision of improveddrying or finishing apparatus and methods for the treatment of moldedpulp articles to give them the dimensional accuracy and/ or degree ofsurface finish that is desired.

Additional objects of the present invention include the provision of anovel form of drying or finishing apparatus which does not have to haveits major components go through the undesirable inertia eifects ofrepeated stop and start steps to treat molded articles whether or notthey have previously been dried, and which is simpler and more ruggedthan prior art machines of this type.

The above, as Well as further objects of the invention, will be morereadily understood from the following description of several of itsexemplifications, reference being made to the accompanying drawingswherein:

Fig. 1 is an elevation, with parts in section, of a drying and finishingapparatus embodying the present invention;

Fig. 2 is a plan view, with parts in section, of the apparatus of Fig.1;

Figs. 3 to 7, inclusive, are detail views illustrating a sequence ofoperational steps involved in the operation of the apparatus of Figs. 1and 2;

Fig. 8 is an elevational view showing the transfer mechanism portion ofthe apparatus of Figs. 1 and 2;

Fig. 9 is an elevational view partly in section along the line 9-9 inFig. 2 of the transfer mechanism of Fig. 8;

Fig. 10 is an elevational view of the feed assembly portions of thetransfer mechanism of Figs. 8 and 9;

Fig. 11 is a schematic showing of a modified construction exemplifyingthe present invention; and

Figs. 12 and 13 are diagrammatic side views of further types ofapparatus exemplifying the invention.

lI-atenlzerl July 3, H9563 According to a preferred embodiment of thepresent invention, wet molded articles are partially free-dried, andwhile they still contain an appreciable moisture content, are subjectedto a drying and finishing operation between a set of complemental heatedpressing dies. A suitable pressing apparatus for this purpose includes aseries of mating pairs of complemental dies, one or both of which may beheated, the series being disposed in an endless or circular path,driving structure is connected to move the series around this path sothat all the individual pairs of mating dies move successively through apredetermined position, operating mechanism is provided to move one ofthe dies of each pair away from and into face-to-face relation withrespect to the other in a fixed transfer zone of the travel path, theother die of each pair being nonretractably, or substantiallynon-retractably mounted, said operating mechanism including loadingelements interconnected for delivering an article to be dried andfinished to one of the dies of each pair while these dies are held apartafter which the dies are brought into face-to-face relation, pressingmeans is connected to press the dies of each pair together as they leavethe transfer zone and to hold them together under heat and pressurethrough a pressing zone that occupies substantially the remainder of thetravel path, said operating mechanism also including unloading structureconnected for receiving a finished article from the open dies in thetransfer zone to remove this article from the apparatus and make way forthe next article to be finished. For maximum efficiency the transferzone should extend over a minimum amount of the travel path along whichthe dies progress.

The individual sets of dies can be arranged either to move around thetravel path in short steps or continuously without stopping except whenthe equipment is shut down. The molded pulp articles fed to the machinecan have a moisture content varying from about 10% to about or morebased on the total wet weight. After finishing in the above apparatusthe moisture content is generally between about 5% and 8%. Where it isdesired to obtain a particularly smooth and even glossy finish on themolded article, the moisture content should preferably be at least about25% when it enters the machine. The lower initial moisture contents arevery effectively used when the articles are to be given a lighterfinishing treatment, as for example to iron out any warpage and restorethe article to substantially its original molded shape with a minimumimprovement of its surface appareance. Below 10% moisture, however, itbecomes commercially impractical to effect such ironing or surfaceimprovement without destroying many of the physical characteristicsdesired in the finished article.

The drying and finishing apparatus of Figs. 1 to 10, inclusive, has amain table or framework Zll which is journalled on a vertical shaft 22.and carries a set of radially disposed die holders 24. Each die holderis generally C-shaped and includes an upper socket 26 and a lower guide28 of tubular form vertically aligned with each other. The upper sockets26 resiliently hold indi vidual die carriers 33 to which upper dies 32(Fig. 3) are securely fastened. In the form shown the resilient mountingis provided by coil springs 34 seated against the blind upper end ofsocket 26 and holding carrier 30 somewhat below the highest or fullyseat position. The resilience not only acts as a control of the dieclamping force but provides a margin of safety should two or morearticles become accidentally loaded on a single die at the same time.

Vertically slidable in the lower guides 23 are elongated shanks 44 towhich are fastened lower die carriers 40 carrying lower dies 42 (Fig.3). The outer portions of each C-shaped holder 2 t also carries, as bymeans of oppositely projecting horizontal pins 46, an opposed pairgreases of pivoted compression links 43. Suitably disposed between eachpair of links is a Wedging roller 50 journaled about a horizontal axisand engageable with a cut-away wedge surface 52 at the lower portion ofshank 44. The shanks also carry independent lifting rollers 54 whichrest upon and cooperate with radially disposed fixed cam segments 56, 57positioned for automatically raising and lowering the lifting rollers,respectively, at the proper times. A collar 45 on shank 44 acts as alower limit stop for the opening movement of the lower dies.

In the above construction the framework is rotatcd by means of electricmotor 58 and an internal Geneva movement including a plurality ofcircular locking sectors 60 and bars 62 defining radial driving slots 63fixed to the cage, along with a rotatable Geneva driver having acooperating annular locking segment 64 concentric with segments 60, anddriving roller 66 driven by shaft 63. The rotating drive is arranged sothat there is one stepping position or circular sector at) for each dieholder 24 and with each revolution of shaft es, the framework is steppeda distance which brings each holder 24 to the position previouslyoccupied by an adjacent holder. In other words, the stepwise rotationcarries each die holder through the same fixed and predeterminedstopping positions between steps. For actuating the compression links48, fixed cam operators 7t 72 are suitably supported to engage with acam-following roller 73 fastened on each pair of the links. Cam 70 (Fig.2) is positioned at the end of a pressing zone and has an inwardlyoff-set portion 74 to effect unlocking of the pressing dies, while cam72 is located at the beginning of the pressing zone and causes the diesto be locked in pressed engagement.

In the shorter or transfer zone between the cam operators 78', 72, thedies carried by the holders are arranged to be opened, unloaded, andhave'fresh articles supplied, for drying and finishing through thebalance of the table rotation. To effect these transfers, a transferunit 100, shown more clearly in Figs. 8, 9 and 10, is mounted alongsidethe framework 20 in the transfer Zone. Unit 190 includes a hollow shaft16 2 journaled in fixed bearings 104 and carrying a drive gear M6meshing with a peripheral ring gear 76 provided on framework 20.Vertically slidable within hollow shaft 162 and also rotatable alongwith this shaft, as by splined interconnection, is a post 108 whichcarries a pair of oppositely directed unloading dies 110, 111 andanother pair of oppositely directed loading dies 112, 113 (Fig. 2). Thelower end of post 108 is supported by a rocker lever 114 having apost-engaging block 116 ad pivoted at 118 for actuation by a cam wheel120. This cam wheel in turn is rotated by means of bevel gears 122(Fig. 1) so as to with the rotation of the main frame 24 Below theoutwardly projecting loading die 113 at position N (Fig. 2) there ispositioned a supply unit 2% for feeding individual molded articles to bepressed. A vertically disposed rack 2 622 is fixed in place and slidablyholds a vertically movable feed platform 294 which is shown as havingbosses 2655 slidably guided on posts 2% forming part of the rack. Attheir tops, the posts 2% can be provided with sockets 2b? for snuglyreceiving the bosses 205 and acting as a pneumatic stop to preventjarring when the platform is permitted to move up in an uncontrolledmanner. Bleed orifices 2il9 can also be provided to allow the platformits full range of upward travel. In the form shown the apparatus isdesigned to dry and/ or finish molded pulp plates or dishes, andplatform 204 is correspondingly shaped to receive a stack of theseplates. The lowest plate in the stack is shown at 210 in Fig. 10, and aset of supports 211, of which two are shown, keeps the stacked platesaligned and prevents them from toppling. For convenience in loading, aportion of the vertically disposed stack guides may be removably held inplace as shown for example by the panel 246 which is slidably held onrack posts 208 and, can be be synchronized 4 latched in its upper orclosed position as by interaction of latch pin 248 with a suitably cutout latch spring 250. Yokes 252 forming the top and bottom of this paneland connected by bars 253 provide convenient manipulating structure bywhich the panel can be grasped and lowered to the open position or movedto the closed position illustrated. Some or all of the supports 211 canadvantageously be carried by the panel 246, preferably in adjustablepositions as by bolts 247, held by jam nuts 249, so as to accommodatearticles of various widths. A hand wheel 26f) fastened to shaft 228enables the lowering of platform 204 when desired.

The platform 204- is linked by means of a pair of chains 212 with a feedratchet gear 214 fixed on rotatable shaft 228 and this gear is connectedfor stepwise advancement by rocker lever 114. Chains 212, one on eachside of the platform, may conveniently be of the endless type loopedaround freely journalled upper sprockets 216, around lower sprockets 218fixed to shaft 223, and secured as indicated at 220 to suitable portionsof the platform. A spring 222 acting through an additional chain 224 andanother sprocket 226 fixed to a common shaft 228 along with sprockets21$ and ratchet gear 214, co operates to urge the loadingplatform'upward. The end 223 of chain 224 can hang free, or be held downas by weight 225.

A ratchet advancing pawl 238 is carried by an arm 236 pivoted to shaft228 and connected for reciprocation by a linkage 234 with rocker lever114. For adjustment purposes, the linkage can be a turnbuckle, asillustrated. The pawl 238 and ratchet gear 214 have inclined teethpointed in opposite directions so that when they are engaged the ratchetgear cannot be rotated in counterclockwise direction as seen in Fig. 9,and the platform accordingly cannot be raised. Although the pawl isshown as disengaged, this is only in the interest of clarity since it isnormally engaged under the influence of bias spring 240.

A release cam 232 is pivotally held on shaft 228 by bar 242 integralwith boss 241. The inner surface of the earn 230 is positioned to clearthe teeth of ratchet gear 214, but the cam has a nose 231 which islocated in the path of pawl 238 and acts to cause the downwardly movingpawl to lift itself up along the nose until the pawl becomes disengagedfrom the ratchet gear. An. adjustable stop bolt 235 and bias spring 233cooperate with the cam bar 242 to fix its position. A control lever 24 ipivoted at 232 is also provided to manually withdraw and interrupt theoperation of the release cam 230 When desired. In addition this lever244 can be placed in the path of panel 246 to automatically stop thefeed when the panel is opened, as for loading.

To assist the transfer dies 112, 113 in picking up the uppermost platesof the loading stack away from the plate below it, a separating deviceis advantageously used. In Fig. 10 the separating device is in the formof constricting structure at the upper end of the stacking passageway,provided by fingers 254 projecting in against the sides of the stack.The fingers 254 leave between them a plate passageway slightly smallerthan a plate diameter, and are located just below the lowest position ofthe transfer die 112 so that only one plate can lie above them. The nextlower plate will be pushed up by platform 204 against the fingers whichcause it to become bowed as indicated at 256 keeping it from nestingengagement with the uppermost plate and greatly simplifying the removalof the uppermost plate.

For simplifying the transfer of the articles being treated from one dieto another, the dies may be perforated and fitted with suction and/ orcompressed air supplies. Control units (Figs. 1 and 2) operated as bycams 82 driven in synchronism with the transfer unit llltl provide thedesired timing of these transfer assisting features. Connections such asslip rings 36 are provided to conduct heating current to the pressingdies 32, 42 on the main arsasso frame 20. In addition a rotary valveassembly 87 can be arranged to establish vacuum and/or compressed airconnections to these dies for operation at desired portions of therotation cycle.

In operation the motor 58 rotates the main frame 29 clockwise as seenfrom above (Fig. 2) through arcuate steps equal to the separationbetween adjacent pairs of dies. The transfer-die-holding shaft 108 isrotated counterclockwise a half turn (180) per. step. The articles to bedried and/or finished are placed on the loading platform which is liftedup to bring the top of the stack against the fingers 254, or to thatheight if the fingers are not used. To lower theplatform for loadingpurposes, the handwheel 26b is rotated clockwise, looking in thedirection of Fig. 9. This rotates ratchet gear 214 past the pawl 233which is lifted out of the way by the inclined teeth.

Referring more particularly to Fig. 2, as the frame 24) rotates, a pairof pressing dies is moved into position A while the loading transferdies 112, 113 are rotated around to interchanged position and verticallyreciprocated. At position A after the completion of the advancing step,the parts are then in the relationship shown in Fig. 3. 1

During the vertical reciprocation one loading die 113 is brought againstthe top of the stacked plates while the pawl 238 is momentarilydisengaged by cam 2324 out of ratchet-holding engagement. The holdingplatform 204 accordingly moves upwardly as far as it can go under theinfluence of spring 222, or up against the loading die above the stack.At the same time suction applied to this leading die causes theuppermost plate to be sucked onto the die and there held in place.

While this loading is taking place, the opposite loading die 112 isbrought down against the open pressing die 42 just below it, as shown inFig. 4 and deposits a previously loaded plate on this die. Suction cannow be cut off from the loading die, applied to the pressing die and/ ora puff of compressed air used to help this deposition.

The final lifting of the loading dies at the completion of the verticaloscillation returns the loading die 112 to the position shown at Fig. 3.This is accompanied by shifting of the pawl 238 in the clockwisedirection so that the ratchet gear 214 is engaged and rotated to carrythe platform 2% back down somewhat from its most ele' vated position.This lowers the stack somewhat and compensates for its springiness whichotherwise might force the upper plates over the top when the downwardpressure of the transfer die is removed.

The teeth of ratchet gear 2114 need not correspond in pitch to theturning required to move the stack the thickness of a plate since thisdownward motion will always carry the stack sufficiently far away fromthe transfer die after the topmost article is picked up by the die. Ifdesired, however, a finer adjustment can be provided as by using two ormore pawls 23$ side by side with their teeth staggered so that thelatching engagement alternates from one to another and moves throughsteps smaller than the spacing of the individual teeth on any one pawl.

The next step in the rotation of frame carries the open pressing dieswith the transferred plate from position A to position B. Cam segment 56herelifts the lower die 42 with its plate up against the upper die 32 asshown in Fig. 5. At the same time or shortly thereafter cam '72 carriesthe pressing link outwardly to the positions shown consecutively inFigs. 5, 6 and 7. At the position of Fig. 6 the wedging roiler St) isbrought into engagement with the wedge surface 52 and the upper die 32has not yet been forcefully engaged so that it may still be suspended byits resilient mounting.

Continued movement of link 43 to the position of Fig. 7 causes the lowerdie to be wedged upwardly by roller 50, compressing the resilientsupport for the upper die and applying the desired pressing to theloading plate.

At about this time heat may be applied to the dies, as by closing anelectric circuit to electric heaters in both dies 32, 42. Alternativelythe heating can be maintained uninterruptedly throughout the rotation ofthe main frame. From position B the closed dies are kept locked by thepressing links and are then stepped through positions C, D, E, F, G, H,J, K without interrupting the pressing. The locking of the compressinglinks can be secured by providing these links 48 with an over-centerholding arrangement as by suitably shaping the wedging surface 52 in themanner shown in the figures.

Upon the movement of the dies through the steps L and M the links 48 arefirst unlocked by cam operator '70 and the lower die permitted to dropby the suitably shaped upper surface of cam segment 57. The diesaccordingly open by retracing the sequence through the positions shownat Figs. 7, 6, 5 and 3. However, at position M the open pressing dieshave between them one of the unloading dies instead of the loading die112 shown in Fig. 3.

When the dies reach position M, or as they are about to move from thereto position A, the vertical reciprocation of the transfer shaft 108carries the unloading die 11% against the lower die 42 just beneath itas in Fig. 4, and with or without the assistance of suitably directedsuction and/or compressed air, the plate that has been through thepressing cycle is transferred to this unloading die. Upon rotation ofthe transfer shaft 108 this unloading die is moved to position P (Fig.2) where it then blows or permits the unloaded plate to drop onto asuitable discharge receptacle or conveyor, not shown.

This unloading sequence of the transfer mechansm, as described above,can be effected at the same time as the loading. In other words, eachstep of the transfer unit corresponding to a step of the main frame 20can include a single vertical reciprocating step which simultaneouslydoes the following operations:

(a) Transfers to unloading die at position M a plate that is carried bythe pressing dies at this position.

(b) Transfers to the pressing dies a plate from a load ing die atposition A, which plate was previously picked up by this loading die atposition N.

(c) Discharges from unloading die at position P a plate that it haspreviously received at position M.

(d) Transfers to a loading die at position N the top plate from the feedsupply stack on loading platform 204.

It will thus be seen that the stepping of the pressing dies fromposition M to position A is accompanied by the unloading of thepreviously pressed plate and the loading of a fresh plate. From positionA the dies then repeat the cycle described above so that the plates arecontinuously being loaded, pressed and discharged.

T he vertical reciprocation can be arranged to take place at any timeduring the stationary dwell period of the framework 2%) betweenrotational steps. So long as the main framework is substantiallystationary when the transfer dies engage the pressing dies, the desiredtransfers will take place even though the transfer die reciprocationstarts or ends while the frame 20 is moving.

Instead of having the framework 20 rotate in discrete steps, itsrotation can be made continuous. For this purpose the transfer apparatusis preferably revised so that the transfer dies follow a path which fora short distance exactly coincides with, but is above, the path of thepressing dies 42. This distance should be sufficient to allow transferby the reciprocating transfer dies. During this coincit ence, thevertical reciprocation of the transfer dies is readily arranged withoutrequiring the critical timing that would otherwise be necessary toassure that the lower pressing die is in the appropriate instant orportion of its rotation when the transfer dies reach their lowest ortransfer position.

One convenient technique for coinciding the travel of the dies is tohave the arms carrying the transfer dies constructed of telescopingsections and suitably guided as by fixed peripheral guides so thatduring the travel of the transfer dies across position M and position Athe arms telescope to carry these transfer dies along an arc of thecircle drawn about the rotating center of shaft 22. The path coincidencecan be extended over the entire transfer zone or can be limited to onesmall portion of this zone for loading and another spaced portion forunloading. Where a single transfer turret is used for both loading andunloading pressing dies reaching only one position, an odd number ofpressing die sets should be used to enable proper operation. In such amodification, the pressing dies should be arranged to go through tworevolutions per machine pressing cycle. It is advantageous in this typeof operation to have an even number of transfer dies, half used forloading and the other half for unloading, these dies alternating aroundthe transfer turret so that the loading dies do not have to do anyunloading and vice versa.

Although a single transfer turret is shown below in connection with Fig.11, separate loading and unloading turrets can also be used, eachengaging the main frame at a diflerent portion of the transfer zone.

The transfer dies which can, according to these modifications, alsorotate continuously about shaft 108 can be operated with the loadingstack on platform 204 by arranging for this platform and its associatedstructure to oscillate about a circular path having its center at shaft108. This horizontal oscillation can then readily be synchronized sothat the vertical reciprocation of the rotating loading will take placewhile the platform is in that portion of its oscillation in which itsmovement corresponds in direction and velocity to that of the transferdies.

If desired, the rotating transfer dies can have their positioning armsfurther guided by interrupting mechanism to slow down or stop theirrotation for a small portion of their travel, during which time thevertical reciprocation is arranged to take place. When the reciprocationis completed the interrupting mechanism releases the arm which can thenbe resiliently returned at a higher than average speed to its properposition in the rotation cycle.

According to a modified form of the present invention, unloading offinished articles is effected by means of an unloading chute which canconveniently be positioned in an appropriate portion of the transferzone below the upper pressing die. The individual upper pressing diescan then be arranged to have the pressed articles adhere to them, as bymeans of suitably applied suction, when the dies are parted. To assurethe accurate dropping of the pressed articles into the unloading chute,the holding vacuum can be released and if desired a puff of compressedair automatically added at the appropriately synchronized instant. Thistype of construction dispenses with the need for unloading dies on thetransfer mechanism. The number of dies carried by shaft MS can theneither be reduced, or all of these dies can be operated as equallyspaced loading dies that rotate with only one small range of therotation travel coinciding with the pressing die rotation.

According to a further phase of the invention, the supply of articles tothe loading stack Zllil for drying and/or finishing can also be arrangedto take place in a continuous manner. For this purpose a feedingapparatus of the type shown in copending U. S. patent application,Serial No. 789,167 filed December 2, 1947, now abandoned is effectivelyused to continuously supply a suitable spaced row of molded articlesdirectly from the forming and/ or preliminary drying unit. An escapementmechanism as shown in that application times the delivery of eacharticle so that one is brought into loading position under a transferdie in time for it to be picked up by the die as it descends.

Fig. ll illustrates the essential elements of such an apparatus. In thisconstruction an assembly of pressing dies can be arranged as a unit 320similar to that of framework 20 in the construction of Fig. 1, exceptthat assembly 320 is arranged for continuous (non-intermittent)rotation. The, upper die of each pressing pair is shown at 332. Atransfer assembly 4190 carrying a set of transfer dies 31.1 is shown asconnected by gear 3'76 with the pressing die assembly so that bothassemblies rotate in unison. The individual transfer dies 311 aremounted on telescopic arms 32?, and adjacent each transfer die there isprovided an aligning fork or shoe 325 shaped to engage the exterior ofthe successive pressing dies 332. The arms 322, shown as four in number,are equally spaced around the periphery of the transfer unit res and arecarried by a plate winch is resiliently secured to gear 376 as by meansof the centering springs 329. The remainder of the transfer unit 409 maybe similar to the transfer unit ltli) in the construction of Figs. 1 to10, with the arms 322 correspondingly arranged to reciprocate along itsaxis of rotation on shaft 3G8.

Arms 322- are resiliently held, as by internally fitted springs, inoutwardly extending position where the dies 311 move through a circularpath defined by the dot-dash lines 331'. However, when the successivetransfer dies reach position 333, the aligning forks 325 are engaged bythe moving pressing dies 332 which force the arms to telescope inwardlyso that the transfer dies follow the dash line path indicated at Duringthis portion of their movement the transfer dies are aligned with andmove congruently with the pressing dies so that vertical reciprocationwill effect the desired transfer of articles to the pressing dies. Atposition 33"? the transfer dies return to their circular path 331 andleave the transfer zone of the pressing assembly 32f During the motionalong path 335 the transfer arms are constrained to travel at an angularvelocity which varies from point to point by reason of theircontinuously changing radii. Resilient holding elements 329 accordinglypermit floating plate 327 to rotate with respect to gear 376 so that thetransfer dies can accurately follow the pressing dies without disturbingthe fixed gear driving connection. When the path 335 is varied withrespect to the pitch or meshing line of the drive gears, the transferturret will also show further changes in angular velocity at theintersection points 333 and 337. The resilient drum mounting arrangementcan also accommodate these further changes.

The articles to be pressed and dried are fed to the transfer assembly406 by means of a conveyor section 450 shown as of the arcuate typehaving a center of curvature and angular velocity identical with thosefor the pressing assembly 3243*. A guide wall 452 is positioned abovecurved conveyor 45f to coact with the projecting portions of transferdies 311 to deflect the dies into a path having a curvature coincidingwith that of conveyor 450. Articles to be molded as indicated at 454 aresupplied to the curved conveyor 450 from a linear conveyor 456. Toaccurately correlate the feed of these articles with respect to themovement of the transfer dies 311, an escapement mechanism is arrangedto suitably time the arrival of successive articles.

In the form shown the escapement mechanism includes a fixed wall 458 anda resilient blade 460 suitably anchored and resiliently held against acam 462 driven from gear 376 through a meshing gear 464. An additionalfixed wall 459 can be placed opposite wall 458 to form between them achannel through which the successive articles 454 will freely pass.Blade 460 is arranged to be moved by cam 462 towards wall 458 to anextent that prevents passage of an article 454. However, during itsrotation the cam permits the blade at the correct moment to withdrawfrom wall 458 and allow an article to be discharged on to the curvedconveyor 450, where it is picked up by a transfer die. Should an articleheld by the escapement mechanism cause closely following articles topile up behind it, auxiliary wall 459 will keep these piled up articlesaligned so that there is a reduced tendency to jam or divert greases notcause an article to slide over or under a previous article held by theescapement.

In operation the apparatus of Fig. 11 can have conveyor 456 fed directlyfrom the dryer or molding unit and conveyor 456 can be the belt conveyoron which the articles are normally discharged from the moldingequipment, as shown in Chaplin Patent No. 2,163,585, or the wire belt onwhich they are carried through a tunnel drier, as described in saidabandoned Randall application, Serial No. 789,167, filed December 2,1947. The articles will be automatically and continuously picked up bythe transfer arms from conveyor 450 in exactly the same manner as theyare loaded on to the pressing dies. Both the path 335 and thecorresponding path over picloup conveyor 454i can very efifectivelyextend over no more than the distance required for the moving articles454 to travel in a time of about onehalf second. However, where fastervertical reciprocating transfer cycles can be used, correspondinglyshorter paths are suitable. An unloading chute 340 may be provided inthe transfer zone to receive the pressed articles ejected from the upperdie by a blast of air as it passes over the chute after the completionof a pressing cycle and before the pressing dies reach the loadingposition.

The pressing dies of the apparatuses of Figs. 1 and 11 are preferablyheated to between about 250 and 450 F. Lower die temperatures can alsobe used but require longer pressing treatments to effect the desireddrying.

The segmental cam constructions shown above in Fig. 2 are advantageouslyincorporated in the construction of Fig. 11. Such cams are not simplerto provide, but in addition they permit opening of the transfer dies inthe pressing zone. Thus at any but the extreme positions of the pressingzone, the links 48 holding a pair of dies closed can have their lowerend manually pushed inwardly, thereby releasing the lower of these diesand permitting them to open. This is a highly desirable operation,particularly when the apparatus is shut down and molded articles carriedby the pressing dies are to be kept from over-heating and possibleburning. It should be noted that the unlocking cam 70 includes a lockingsection 71 to assure the proper closing of any dies that have beenopened in the pressing zone so that the open dies need not be watchedbut will be automatically closed without interfering with the operationof this cam. To the same end a corresponding relifting cam 59immediately precedes the lowering cam 57. As shown more clearly in Figs.3 and 4, the lowering cam can be of the positively operating type forassuring that the lower dies stay down during the transfer operation.

Another feature of the segmental cam construction is that the tilting,raising and lowering cams are thereby relieved of most of the forcesrequired to eifect' the desired pressing. The pressing is effected inthe construction of Fig. 1 for example practically exclusively by theengagement of wedging rollers 50 with wedge surfaces 52. The lifting andlowering cams do nothing more than bring the lower dies up toface-to-face relation with the upper dies where the pressing can begin.The tilting (locking and unlocking) cams only efiect closing of the diesfrom face'to-face relation to the pressing position and then releasing,at the beginning and end of the pressing zone; they are entirelyinoperative during the remainder of the travel path.

According to the present invention the portion of the turret path inwhich the dies must be open for transfer purpose, is held down to a verysmall fraction of the total path.

For this purpose the loading mechanism and the unloading mechanism arespaced along the turret path so 'dies.

. l0 that they c'oact with portions of the path separated by about thedistance between adjacent pairs of pressing According to a furthermodification of the present invention the loading on and unloadingfromthe pressing dies is accomplished by simple chute arrangementssimilar to that shown for the unloading chute 340 in the construction ofFig. 11. I

Fig. 12 schematically shows the essential elements of a chute type ofloading deviceexemplifying the present invention. In this View two setsof upper pressing dies 532, 533 and lower pressing dies 542, 543 areshown in adjacent positions of pressing die travel of the continuous(non-intermittent) type, the horizontal travel direction being indicatedby the arrow 511. The upper dies are relatively fixed against verticalmovement. Each lower die, however, is connected for automatic verticalreciprocation from a high position in pressing engagement with the upperdies to a low position indicated by the die 542.

Around each lower die and horizontally movable therewith is shown afunnel type of loading chute 550. These chutes are fixed with respect tovertical movement and have their lower openings 560 positioned closelyadjacent the upper edge of the lower dies when in their lowest orloading position. i

At a predetermined portion of the horizontal travel path there isprovided a fixed loading conveyor or slide 556 positioned to receiveindividual articles 554 and feed them in suitably timed relation intothe successive chutes 550 as they pass by. An escapement mechanism suchas the one shown in the construction ofFig. 11 can be connected for thispurpose. In addition the loading conveyor is so located that the lowerpressing dies are in their lower position when the articles are droppedinto the loading chutes.

By reason of the tapered character of these chutes the articles 554 fallin a guided manner through the lower chute openings 560 so that theyland, properly positioned, on the lower dies, notwithstanding somevariation in the exact location of the continually moving chute withrespect to the loading conveyor 556. A suitable time after the loading,the lower dies are moved up as indicated by the die 543, carrying theloaded article into pressing engagement with the upper dies. The engageddies then move though a pressing zone and finally are again opened tounload the pressed articles for example from the upper dies by means ofan unloading chute such as that shown in Fig. 11.

If desired the feed of conveyor 556 can be arranged to be vigorousenough to at least partially throw the articles across the hopper-likechute 55% so that they are brought into engagement with the far wall ofthis chute and settle down into place as indicated in Fig. 12. The useof vertical hopper walls where they are engaged bythe articles being fedis of advantage inkeeping the articles from coming to rest in tiltedcondition with one edge resting on the hopper, and the opposite edge inthe die. However, the hopper walls that are on the sides that extendacross the direction of die travel (arrow 511) are prefen ably sloped toaccommodate variations in article feed.

It is noted that the usual guide ring around the margin of the lowerdie, by reason of its tapering guide Walls, assists in guiding thefalling article into its proper position.

Where the articles to be pressed are very light in weight and ofgenerally dished shape, it is advantageous to have the lower dies of thefemale type as shown in Fig. 12, so that the articles 554 can be droppedwith the convex face directed downwardly. This orientation providessomewhat more rapid dropping with less tendency to bounce against thesides of the chute, and more accurate alignment on the die. Furthermore,the articles after pressing are more readily and accurately blown oilfrom the upper dies which usually are of the smooth type used to providea high finish. However, the converse die positioning can be used 'ifdesired.

Although in the various constructions described in Figs. 1 to 12inclusive the pressing of generally circular articles is illustrated,non-circular articles can also be treated by merely suitably shaping thevarious dies. Thus square or rectangular dishes or trays, or the moldedtype of eg containers or eg -crating flats are particularly well adaptedfor pressing in any of the above types of equipment.

Fig. 13 shows a further embodiment of simplified loading device. Thisview corresponds generally to that of Fig. 12 but shows an inclinedconveyor or slide 656 down which dished articles 654 to be molded aresupplied so that they move down to the low end. At this end a resilientrestrainer such as a spring finger 657 keeps the articles from fallingoff but in a position that exposes a concave portion of the article inthe path of a pressing die 642. This die is of generally convex shapecorresponding to that of the article 654, and in moving along indirection 611 catches the projecting concave portion of article 654 atthe restrained position, pushes back the restraining finger and carriesalong the article thereby loading itself. After loading, the dies can beclosed in any desired manner.

The type of apparatus shown in Fig. 13 is particularly well suited foruse with articles of rectangular or square outline since such articlescan be'easily and accurately guided into the restrained position shown.However, articles of circular or other non-rectangular outline can alsobe very effectively loaded with the apparatus. Where a conveyor is usedinstead of the slide shown at 656, the restraining finger 657 should besufiiciently strong to hold back articles impelled by the conveyingaction alone. The apparatuses of Figs. 12 and 13, although shown inconnection with non-intermittent pressing die rotation, can also be veryeffectively used with a pressing die assembly that rotates in shortsteps as in the construction of Fig. 2.

Whereas twelve sets of dies are shown in the assemblies of the abovefigures, any number, more or less than twelve, can be used. As many assixteen or even twentyfour make a very effective assembly having aproductive capacity that is unusually high in relation to the cost ofthe apparatus. This also improves the productive effi ciency of theapparatus because the greater number of pressing dies can be used withthe same small transfer device which extends over the same few numbersof pressing positions. Theloading assemblies of Figs. 12

and 13 can be combined with unloading devices such as unloading chutesby placing one unloading device adjacent a loading assembly so that theyare spaced by about the distance between adjacent pairs of pressingdies, to provide a pressing zone of maximum extent, as shown for examplein the construction of Figs. 1 and 2.

As many apparently widely different embodiments of the invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that the invention is not limited to the specific embodimentsthereof except as limited by the appended claims. Thus the transferdevice of the construction of Fig. 2 can be used to feed to and unloadarticles from other article handling devices such as printers,labellers, etc.

What is claimed is:

l. A pressingapparatus for subjecting molded pulp articles to afinishing treatment which comprises a rotatable turret, means forrotating said turret, a plurality of die means mounted in spacedrelationship to each other on said turret, each of said die meansincluding a mating pair of pressing dies, at least one of said diesbeing a movable die which is movable toward and away from its matingdie, a cam follower connected to said movable die and adapted to beactuated by a cam track adjacent said turret for moving said movable dietoward its mating die, a. wedging surface connected to said movable die,a link mechanism having one end pivotally connected to said turretadjacent said movable die and having a cam follower at its opposite end,a wedging roller mountedon said link mechanism and adapted to bewedgingly engaged with said wedging surface, a discontinuous cam trackadjacent said turret for actuating the cam follower on said linkmechanism to move said link mechanism in one direction for engaging saidwedging roller with said wedging surface and. a second discontinuous camtrack for actuating the cam follower on said link mechanism to move saidlink mechanism in the opposite direction for disengaging said wedgingroller from said wedging surface.

2. The apparatus of claim 1 wherein said turret is constructed andarranged to be rotated intermittently.

3. The apparatus of claim 1 wherein said turret is constructed andarranged to be rotated continuously.

4. The apparatus of claim 1 wherein said link mechanism is adapted to bemanually moved away from said wedging surface when its corresponding diemeans is inbetween said discontinuous cam tracks.

5. A pressing apparatus for subjecting molded pulp articles to afinishing treatment which comprises a rotatable turret, means forrotating said turret, a plurality of die holding means mounted in spacedrelationship to each other on said turret, each of said die holdingmeans comprising a support on one portion of which is mounted an upperpressing die and on another portion of which is provided a sleevecoaxially spaced from said upper pressing die, a lower pressing diehaving a stem slidably mounted for vertical movement in said sleeve, acam follower depending from the lower portion of said stem, a cam trackmeans adjacent the rotational path of said turret and adapted to coactwith said cam follower, a link mechanism having one end pivotallyconnected to said sleeve, a cam follower at the opposite end of saidlink mechanism, a wedging roller positioned on said link mechanismintermediate its pivoted end and the end having the cam follower, secondcam track means for meeting with the cam follower on said link mechanismfor rocking said link mechanism in such a manner that said Wedgingroller is moved into frictional engagement with said wedging surface atone portion of the rotational path of said turret, and for rocking saidlink mechanism in the opposite direction to move said wedging rolleraway from frictional engagement with said wedging surface at anotherportion of the rotational path of said turret.

6. The apparatus of claim 5 wherein said upper die is resiliently urgedtoward said lower die.

7. The apparatus of claim 5 wherein said second cam track meanscomprises two cam track segments, each of which extends around arelatively short portion of the rotational path of said turret and whichare spaced from each other in the direction of said rotational path.

8. The apparatus of claim 5 wherein said turret is constructed andarranged to be driven intermittently.

9. The apparatus of claim 5 wherein said turret is constructed andarranged to be driven continuously.

References Cited in the tile of this patent UNITED STATES PATENTS1,492,510 Escobales Apr. 29, 1924 1,778,934 Chapman Oct. 21, 19301,951,940 Manson Mar. 20, 1934 1,959,327 Adams May 22, 1934 1,963,134Keiding June 19, 1934 1,965,732 Bisterfeld July 10, 1934 1,966,471Walters July 17, 1934 2,000,761 Kohler May 7, 1935 2,337,581 Wiley Dec.28, 1943 2,388,828 Chaplin Nov. 13, 1945 2,624,956 Chaplin Jan. 13, 19532,686,587 Johnson et al. Aug. 17, 1954

1. A PRESSING APPARATUS FOR SUBJECTING MOLDED PULP ATRICLES TO AFINISHING TREATMENT WHICH COMPRISES A ROTATABLE TURRET, MEANS FORROTATING SAID TURRET, A PLURALITY OF DIE MEANS MOUNTED IN SPACEDRELATIONSHIP TO EACH OTHER ON SAID TURRET, EACH OF SAID DIE MEANSINCLUDING A MATING PAIR OF PRESSING DIES, AT LEAST ONE OF SAID DIESBEING A MOVABLE DIE WHICH IS MOVABLE TOWARD AND AWAY FROM ITS MATINGDIE, A CAM FOLLOWER CONNECTED TO SAID MOVABLE DIE AND ADAPTED TO BEACTUATED BY A CAM TRACK ADJACENT SAID TURRET FOR MOVING SAID MOVABLE DIETOWARD ITS MATING DIE, A WEDGING SURFACE CONNECTED TO SAID MOVABLE DIE,A LINK MECHANISM HAVING ONE END PIVOTALLY CONNECTED TO SAID TURRETADJACENT SAID MOVABLE DIE AND HAVING A CAM FOLLOWER AT ITS OPPOSITE END,A WEDGING ROLLER MOUNTED ON SAID LINK MECHANISM AND ADAPTED TO WEDGINGLYENGAGED WITH SAID WEDGING SURFACE, A DISCONTINUOUS CAM TRACK ADJACENTSAID TURRET FOR ACTUATING THE CAM FOLLOWER ON SAID LINK MECHANISM TOMOVE SAID LINK MECHANISM IN ONE DIRECTION FOR ENGAGING SAID WEDGINGROLLER WITH SAID WEDGING SURFACE AND A SECOND DISCONTINUOUS CAM TRACKFOR ACTUATING THE CAM FOLLOWER ON SAID LINK MECHANISM TO MOVE SAID LINKMECHANISM IN THE OPPOSITE DIRECTION FOR DISENGAGING SAID WEDGING ROLLERFROM SAID WEDGING SURFACE.